WTTS from ISO to SPITZER
Authors:
          Àgueda Gras-Velázquez, Dublin Institute for Advanced Studies
          Tom P. Ray, Dublin Institute for Advanced Studies

Abstract:
               Using data from the photometer onboard the Infrared Space Observatory we have compiled the SEDs of a dozen Weak-line T Tauri Stars (WTTS), belonging to a number of molecular clouds, and found IR excesses indicating the presence of circumstellar disks. Canonically, and up until recently, WTTS were thought to be devoid of circumstellar matter, and to form a possibly separate class of pre-main sequence stars from the Classical T Tauri Stars (CTTS). Our results would suggest that a continuous spectrum of circumstellar disks may be present, of decreasing mass, from CTTS to WTTS. SPITZER has already observed a large number of WTTS. Following up on our ISO research, we present some initial WTTS SEDs using MIPS photometry.